CSL Behring announced results of a Phase 3b study that showed that a balanced, human 4-factor prothrombin complex concentrate (PCC) is as effective as the current standard of treatment in stopping bleeding in patients receiving vitamin K antagonist therapy (eg, warfarin). Currently, fresh frozen plasma is the standard treatment for warfarin reversal.

This was an open-label, randomized, multicenter study to assess the efficacy, safety and tolerance of human 4-factor PCC to plasma for rapid reversal of acute major bleeding in patients receiving warfarin therapy. The study enrolled 212 patients. The primary endpoint was hemostatic efficacy with respect to the adequacy of stopping an ongoing major bleed within 24 hours from the start of infusion. The secondary endpoints evaluated plasma levels of major clotting factors (Factors II, VII, IX, X, proteins C and S); time to INR correction; number of transfusions, amount of blood products used, and hemostatic agents; and safety and tolerability (including all-cause mortality).

The study results showed that the hemostatic efficacy of 4-factor PCC was comparable to plasma at 24 hours in patients who required urgent reversal of warfarin therapy (72.4% and 65.4%, respectively). Additionally, the co-primary efficacy endpoint analysis showed that the 4-factor PCC was superior in achieving target INR correction within 30 minutes at the end of infusion as compared to plasma (62.2% and 9.6%, respectively). Four-factor PCC was also superior to plasma in rapidly and safely raising the levels of clotting factors II, VII, IX, X, and anticoagulant Proteins C and S at the same 30 minutes post-treatment time point (P values<0.0001).